Black copper and Blue copper Marans question

[SemiQ]

Okay, so I read somewhere that if you bred a black copper Marans and a blue copper, 50% of the chicks will be black and the other 50%,blue. My question is that, I heard that this would still be considered pure? Is this true?

If so, wouldn't there be leakage in the down? Please explain as I'm confused and can't seem to wrap my head around genetics quite yet.

 

[Sneebsey]

Blue is an incompletely dominant dilution gene which almost exclusively effects black pigment;

Black x Black: 100% Black
Blue x Black: 50% Blue, 50% Black
Blue x Blue: 25% Black, 50% Blue, 25% Splash
Blue x Splash: 50% Splash, 50% Blue
Splash x Splash: 100% Splash

As you see, blue birds themselves are not pure for the blue gene, but this does not matter; as the gene is incompletely dominant, it has an effect on the eumelanin (black pigment), albeit less of one than a double-dose of the gene.

Without the addition of a single copy of the blue gene, the birds would be black-copper, hence why they are still pure regardless, and why you will not see any leakage.

 

[nicalandia]

Blue is an incompletely dominant dilution gene which almost exclusively effects black pigment;

Black x Black: 100% Black
Blue x Black: 50% Blue, 50% Black
Blue x Blue: 25% Black, 50% Blue, 25% Splash
Blue x Splash: 50% Splash, 50% Blue
Splash x Splash: 100% Splash

As you see, blue birds themselves are not pure for the blue gene, but this does not matter; as the gene is incompletely dominant, it has an effect on the eumelanin (black pigment), albeit less of one than a double-dose of the gene.

Without the addition of a single copy of the blue gene, the birds would be black-copper, hence why they are still pure regardless, and why you will not see any leakage.

That is quite a good explanation, but I would like to add that blue on the ER birchen allele does tend to fade pheomelanin(gold pigment) an example of this are the "lemon blues" and splash lemon blues they care considerable more diluted than the standard brown reds(ER s+) birds

The effect is not very drastic on Marans because they have some form of red enhancers but it's noticeable on some lines that are not so red enhanced, some can even be called "Lemon Blues" if you ask me

 

[Sneebsey]

Theoretically good BCM should have both Mahogany and be Melanised, but some are better than others and irresponsible breeding does occur, particularly with a breed so popular as these.

@nicalandia I omitted the pheomelanin effect for simplicities sake, but have noticed it in my mixed flock; I have a particular pullet from this year who is almost straw-coloured other than her head and tail, shall have to take a picture for you as she really does exemplify the effect, quite striking in my view.

 

[SemiQ]

Blue is an incompletely dominant dilution gene which almost exclusively effects black pigment;

Black x Black: 100% Black
Blue x Black: 50% Blue, 50% Black
Blue x Blue: 25% Black, 50% Blue, 25% Splash
Blue x Splash: 50% Splash, 50% Blue
Splash x Splash: 100% Splash

As you see, blue birds themselves are not pure for the blue gene, but this does not matter; as the gene is incompletely dominant, it has an effect on the eumelanin (black pigment), albeit less of one than a double-dose of the gene.

Without the addition of a single copy of the blue gene, the birds would be black-copper, hence why they are still pure regardless, and why you will not see any leakage.

That is quite a good explanation, but I would like to add that blue on the ER birchen allele does tend to fade pheomelanin(gold pigment) an example of this are the "lemon blues" and splash lemon blues they care considerable more diluted than the standard brown reds(ER s+) birds

The effect is not very drastic on Marans because they have some form of red enhancers but it's noticeable on some lines that are not so red enhanced, some can even be called "Lemon Blues" if you ask me

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Interesting! It's good to know this information and this is helping me understand genetics abit more. Thank you very much!